Effect of palm kernel shell (pks) as coarse aggregate on the compressive strength of Revibrated concrete.

Abstract

The effect of palm kernel shell (PKS) as coarse aggregate on the compressive strength of re-vibrated concrete is presented. Preliminary tests were carried out on the aggregates and the Palm Kernel Shell (PKS) to determine their physical properties. A water-cement ratio of 0.60 and a concrete mix design ratio 1:2:4 were used to cast a total of 56 concrete cubes: a set of eight (8) concrete cubes with partial replacement of PKS (0, 5, 10, 15, 20, 25, 30%) for granite (100, 95, 90, 85, 80, 75, 70%) respectively. A total of 26 cubes were non-revibrated and remaining 26 cubes revibrated. The revibration was done for 60 seconds at time interval of 10minutes for 1hour (60 minutes) within setting time. 26 cubes were place on 7days curing, and the remaining 26 cubes, on 28days. The result of both fresh and hardened concrete after curing for 7 and 28 days, showed that increase in the percentage replacement of crushed granite with palm kernel shell reduced work-ability and compressive strength of the concrete. However, the maximum compressive strength of the concrete cubes was 20.63N/mm2 at 95% crushed granite and 5% PKS and the minimum is 6.08N/mm2 when Palm kernel Shell is added at 30% replacement respectively. The compressive strength of concrete at 5% PKS replacement for granite satisfied the class of lightweight concrete grade C15.